The present invention relates to improved catheters and to kits comprising them, and, in particular, to catheters securable to bodily tissues, used in the diagnostics and in the treatment of fistulae, sinuses and the like, and to kits comprising them.
A catheter is a medical device, shaped as a generally elongated tubular member and made to be pushed into and inserted through a bodily cavity, lumen, fistula, sinus, blood vessel or other passage. A fistulae is a pathological bodily passage whose contour or path within the body is usually irregular and not known in advance. It is to be understood that a general term used hereinbelow for bodily cavities, lumens, fistulae, sinuses, blood vessels and other bodily passages, is passage. It is further understood that all passages comprise an inner surface.
Catheters comprise at least one fluid conduit along at least part of their lengths. Catheters of numerous designs, serving different medical uses, are known in the art. A common use of many types of catheters is the draining of bodily fluids from a patient""s body cavity, by conducting them through a fluid conduit disposed within the catheter and rejecting them outside of the patient""s body. However, many other catheter types, intended for numerous and different uses, are known.
Catheters incorporating inflatable and expandable member or members, usually called balloons, are known. Well known among them, and incorporating features found in many such devices, is xe2x80x9cFoley catheterxe2x80x9d whose mode of operation is described hereinbelow. Foley catheter are designed to be inserted into the urinary tract and to drain and reject the urine outside of the patient""s body. Foley""s catheter comprises an elongated tube having a distal end and a proximal end, a working section extending distally from the proximal end and two internal, generally parallel fluid conduits in fluid isolation between themselves and disposed along the inner side of said tube. One fluid conduit is an inflating conduit and is in fluid communication between an expandable balloon extending from the distal end of the catheter""s tube and an inflating port positioned in the working section of the catheter. The other conduit is a drainage conduit and is in fluid communication between a drainage port located in the working section of the catheter and the outer surface of the catheter""s tube via one or more orifices passing between the wall of said tube and the drainage conduit, said orifices are disposed along the tube and proximally away from said balloon. This catheter is passed through the urinary tract and into the bladder, whose diameter is much larger than that of the urinary tract. Then the balloon is inflated and expanded via the inflating port and the inflating conduit to a sufficiently large diameter. The expanded balloon abuts the bladder and anchors the catheter in place by preventing its dislodging through the urinary tract and outside of the patient""s body. Then the urine flows through the orifices, into the drainage conduit and to the drainage port, from which the urine is discharged out of the patient""s body.
Other catheters are shown in many US and other patents. For example, U.S. Pat. No. 4,445,892 discloses a catheter device that functions as an endoscope, provided with two spaced apart and expandable balloons used in the endoscopic visualization of a length of a blood vessel between said two balloons. U.S. Pat. No. 5,898,850 discloses a treatment accessory serving as a sheath and a guide for a cytology brush used for the removal of samples from a passage. U.S. Pat. No. 5,152,772 describes a catheter carrying two spaced apart expandable balloon and a retractable blade disposed therebetween. U.S. Pat. No. 5,895,400 discloses a sweeping brush carried within a catheter and used in the removal of material such as thrombus from arteries. Numerous other U.S. Patents disclose catheters that teach the use for many other highly varied purposes.
Catheters are often made of soft materials, such as latex When the passage into which the catheter is pushed and inserted is not straight, a soft catheter might collapse and fold if pushed hard enough. A collapsed or folded catheter no longer advances through the passage. The catheter material is sometimes stiffened either by using stiffer materials or by the insertion of stiffeners into the soft matrix of the catheter, thus lowering the chance of a catheter collapse or folding. On the other hand, too stiff catheters might penetrate through the passage walls and injure the healthy tissue. The determination of the preferred catheter stiffness for a particular passage contour and length depends largely on the surgeon""s experience and judgement.
In order to overcome this difficulty, a guide wire is often used. A guide wire is a wire whose diameter is smaller than that of the conduit inner diameter of the catheter so that it could pass through the catheter. Guide wires are made of a fairly stiff material such as hard plastic material or metal, permitting the guide wire to transmit relatively large compressive forces in the general direction of the guide wire axis. When inserted into a catheter, the guide wire stiffens it and permits the pushing of the catheter into a passage with a lower risk of catheter folding or collapse. There exists a variety of guide wires made of different materials and having different diameters, offering their users a choice of a wide range of stiffnesses, Catheters made to utilize guide wires often include a special small diameter, inner tubule disposed within their main tube for containing the guide wire, said tubule is usually in fluid isolation from any other conduit. Sometimes a guide wire is first inserted into the passage, bent and shaped to follow the passage contour and then a catheter is pushed into the passage while sliding along the guide wire. In other cases, a first catheter is first passed through the passage, a guide wire to be used by a second catheter is then inserted into the first catheter and pushed through it, thus the guide wire is shaped according to the passage contour, the first catheter is then extracted off the patient""s body while leaving the shaped guide wire in place, and a second catheter is pushed along the guide wire. Other methods of using guide wires are known.
Catheters are elongated tubular members, insertable into passages, often used for the introduction of medical preparations into particular body parts. Their proper sealing capability, for preventing medical preparations from reaching undesirable body parts, is of utmost importance for proper medical treatment, as is their secure positioning.
According to the present invention there is provided an improved catheter capable of providing improved sealing along passages, as well as a secure and selectable engagement to passages at desired locations along said passages. The present invention further provides for catheters especially adapted for the treatment of fistulae by aiding in the determination of the contours of fistulae and in dispensing medical drugs and other medical preparations for their diagnostics and treatment. The present invention still further provides for kits containing catheters according to the present invention and other medical supplies required during the use of said catheters.
Also according to the present invention, a catheter is provided with an outwardly expandable balloon extensible from the catheter""s circumference wherein the external surface of said balloon actuates means providing for improved sealing and high frictional forces between said expanded balloon and the passage into which it is inserted. This improved sealing divides said passages into a proximal section and a distal section, separated by said balloon, and isolates one section of the passage from the other, lowering the likelihood that material dispensed in one section of the passage might flow across the balloon to its other section, thus preventing backflow. This isolation is important during the dispensation and the application of drugs, contrast madia, tissue sealants and the like along said passages or into cavities joining them, or for draining said passages and cavities.
Additionally, the high frictional forces secure and anchor the catheter to the patient""s body and prevent the catheter""s inadvertent dislodging. Thus, any medical activity could be performed without fear of dislodgement of the catheter or of undesireable fluid flow along the passage. If desired, the balloon could then be deflated and the catheter be moved to another location within the passage, or the catheter could be taken out of the patient""s body. This novel feature of the invented catheters permits the long term securing of catheters to a passage, thus often eliminating the need for sutures.
According to one embodiment of the present invention, said outwardly expandable balloon extensible from the catheter""s circumference is provided with a radially and externally protruding circumferential rib near the balloon""s largest expanded radius and surrounding it, so as to provide for good sealing and high frictional forces between said expanded balloon and the passage into which it is inserted.
According to another embodiment of the present invention, said catheter is provided with a balloon and with a plurality of elongated, relatively stiff, circumferentially disposed, axially oriented, rods, wherein one end of said rods being attached to the catheter outer surface away from said balloon and the other end of said rods rests on said balloon, said rods pointing in the general direction of the catheter axis while said balloon is fully deflated. Flexible webs extend between said rods, forming a shell. When said balloon is expanded while at any selected position within a passage, said rods are pushed against and into the inner surface and the tissue of said passage, therefore anchoring the catheter to said passage at a selected position. During the balloon""s expansion said webs expand to form a generally conical shell, sealing said passage for flow through said shell and along said balloon.
According to yet another embodiment of the present invention, the external surface of said balloon is roughened so as to provide for improved sealing and higher frictional forces between said expanded balloon and the passage into which it is inserted, improving the sealing in the contact area between the balloon and the passage inner surface, and securing and anchoring the catheter to the patient""s body.
Fistulae are pathologically created passages whose contour or path within the body is usually irregular, and are among the most likely passages to be treated by the catheter of this invention. Fistulae tend to suppurate or to be filled by bodily fluids and other materials, causing infections which are difficult to heal. Currently, many fistulae are removed by surgical intervention. The surgical treatment calls for a knowledge of the fistula""s path because some of the fistulae paths pass too close to body parts or organs that may not be operated on or might be harmed during a fistula operation. Currently, a fistula path can usually be determined only by surgery: Only at that stage can the surgeon determine whether or not the fistula""s repair is possible and proceed with the operation.
It is also a purpose of the present invention to provide catheter for the opening of fully or partially blocked passages by inserting, securing and expanding the catheter""s balloon near the blocked area. A blocked bodily passage may be opened by injecting into said passage, under sufficiently strong pressure, an injectable material. The injectable material could by oil, vaseline or other suitable material and it could also serve other functions such as a lubricant. Alternatively, or in addition to injection, the catheter""s balloon may open blocked passages or sections thereof during its expansion. Once a blocked area is opened, the catheter can be further inserted and the opening procedure be repeated as necessary. When the passage""s contour is cleared and the catheter is fully inserted as is necessary, a contrast media for x-ray or for other imaging methods is inserted through the catheter into and along the passage, permitting the elucidation of the shape and of the location of the passage by non surgical methods. It is to be understood that media is used hereinbelow as a general term for x-ray contrast media, for contrast enhancing material used by other methods, as well as for dye and for lubricant.
It is another purpose of the present invention to provide catheter used for the debriding of the inner surface of a passage in order to permit its subsequent treatment by the application of medical preparations.
It is yet another purpose of the present invention to provide another catheter for the application of drugs used in the treatment and healing of the inner surfaces of a preferably debrided fistulae.